Diesters of saturated aliphatic dicar-boxylic acids containing both oxygen and sulphur in the chain



United States Patent 6 Claims. (Cl. 260481) This application is a division of our application Serial No. 846,230, filed October 14, 1959 (now US. Patent No. 3,038,805, issued June 12, 1962).

This invention relates to photographic silver halide emulsions, and more particularly, to an improved means for sensitizing such photographic silver halide emulsions.

A number of methods have been previously described for increasing the sensitivity of photographic silver halide emulsions, other than methods of optical or spectral sensitization, which involve the incorporation of certain colored compounds or dyes in the emulsions. The incorporation of such dyes in the emulsions increases the optical range of sensitivity, and for this reason such dyes are commonly referred to as optical or spectral sensitizing dyes. It is also well known to increase the sensitivity of photographic emulsions by addition of sulfur compounds capable of reacting with silver salts to form silver sulfide, or with reducing agents (compounds of these types are also naturally present in gelatin), or with salts of gold or other noble metals, or with combinations of two or more of the aforementioned compounds generally known as chemical sensitizers. Such chemical sensitizers are believed to react with the silver halide to form, on the surface of the silver halide, minute amounts of silver sulfide or of silver or of other noble metals, and these processes are capable of increasing the sensitivity of developing-out emulsions by very large factors. The process of chemical sensitization, however, reaches a definite limit beyond which further addition of sensitizer, or of further digestion with the sensitizer present, merely increases the fog of the photographic emulsion with constant or decreasing speed.

We have now found a means of further increasing the sensitivity of photographic emulsions which may be applied even though the ordinary processes of chemical sensitization have been carried to the effective limit of the photographic emulsion in question. Our process is to be distinguished from hypersensitization, which is produced by bathing a finished coating with water or with solutions of ammonia, amines or silver salts. Such processes act primarily on optically sensitized photographic emulsions and tend to increase the free silver ion concentration of the emulsion and greatly diminish its stability. Our process is also to be distinguished from hypersensitization by mercury vapor, which gives a transitory effect which is lost on storage of the film. The compounds used in our invention do not appear to be chemical sensitizers in the usual sense, since they increase speed by their presence during exposure and processing and require no digestion with the photographic emulsion to produce an increase in speed, nor does their chemistry indicate that they are likely to react with silver halide under normal emulsion conditions.

The novel sensitizers of our invention are quite unique in that the eliects produced are additive in photographic emulsions which have .already been sensitized to their optimum, or near-optimum, with conventional chemical sensitizers, such as labile sulfur compounds. The novel sensitizers of our invention, however, can be used to sen- 3,194,83 Patented July 13, 1965 sitize photographic silver halide emulsions containing no other sensitizers, if desired. The novel sensitizers of our invention are not strictly chemical sensitizers, since chemical sensitizers do not generally provide the additive effects of the type mentioned.

It is, therefore, an object of our invention to provide photographic silver halide emulsions which have been sensitized with various non-polymeric compounds containing a plurality of sulfur atoms. Another object of our invention is to increase the sensitivity of ordinary photographic silver halide emulsions which have been sensitized with chemical sensitizers, such as compounds containing labile sulfur atoms, or gold-containing compounds. Other objects will become apparent from a consideration of the following description and examples.

According to our invention, we have found that the sen sitivity of an ordinary photographic silver halide emulsion can be materially increased by incorporating therein nonpolymeric open-chain compounds, which can be characterized as polyoxathioethers. These non-polymeric com pounds contain their sulfur atoms in the form of thioether linkages. By thioether linkages, we mean a linkage wherein the sulfur atom is divalent and is joined to two nonoxocarbonylic carbon atoms. Compounds useful in sensitizing photographic silver halide emulsions according to the present invention are to be distinguished from the polymeric thioether compounds described in US. patent application Serial No. 779,874, filed December 12, 1958, by J. R. Dann and J. J. Chechak (now US. Patent 3,046,134, issued July 24, 1962). The polymeric compounds described in this latter application are generally characterized as having high molecular weights and as containing characteristic repeating units or groups.

The sensitizing compounds useful in practicing our invention are non-polymeric and can be represented by the following general formula:

wherein R represents a member selected from the class consisting of hydroxyl, alkoxyl containing from 1 to 4 carbon atoms and carbamyl radicals, R represents a mem ber selected from the class consisting of hydrogen and methyl, each of X and X is a different divalent radical selected from the class consisting of oxygen and sulfur atoms, m is an integer of from 0 to 1 and n. is an integer of from 0 to 2. Typical alkoxyl radicals (R) include.

METHOD A The reaction of a mercaptan with a dihalide METHOD B The reaction of a halide with sodium sulfide 2RBr+Na S RSR-f-ZNaBr The compounds of Formula 1 above, wherein R represents a carbamyl group, can be prepared according to the following method:

METHOD C These methods of syntheses are illustrated in the follow ing examples:

Example 1.Preparation f l,14-dihydroxy-6,9-di0xa- 3,12-dithiatetrcrdecane NMCO 2HOOHZCH3SH CICEZCHZOCHZCHZOCHZOH2C1 HoOHQCHZSCHZCI'IZOCH2CH2OOH2OH2SCH2CHZOH Z-mercaptoethanol, 15.6 g. (0.2 mole), and 1,2-bis(2- chloroethoxy )ethane, 18.7 g. (0.1 mole) were dissolved in 50 ml. of ethanol and mixed with 50 ml. of water con taining 0.1 mole of sodium carbonate. The reaction mixture Was heated under a reflux condenser on the steam bath for 20 hours, the solvent removed under vacuum, and the product separated from the sodium chloride formed, by extraction with hot absolute ethanol and ethyl acetate. The solvents were removed from the combined extracts and the product was distilled. B.P. 220230 C./ 3 mm.

Analysis.-Calcd. for C H S O C, 44.4; H, 8.1; S, 23.7; mol. wt., 270. Found: C, 44.5; H, 8.0; S, 23.3; mol. wt., 277.

Example 2.-Preparati0n of 3,6,12,18,21-pen-t0xa- 9,15-dithiatricosane ZCHZOHflO CHzCHzO CHzCHzBI NazCOa CH3OH20,CHQCHZCHOQCHZSCHgCHzO CH CHzSCHgOHgO CHgCHzO CH CH in vacuum gave the product boiling at 214-218 C./ 1 mm.

H, 9.2; S. I

An:alysis.-Calod. for C H O S C, 51.9; 17.3. Found: C, 52.0; H, 9.2;.S, 17.6.

Example 3..Prepamti0n of 3,6,12,15-tetra01' '9-thiaheptadecane C H OCH CH OCH CH SCH CH OCH CH OC l-li Example 4 .-Preparation 0-) 2,8,11,17-retr0xa 5,14-dithia0ctadecane Na 2CH3OGHzCHzBr+HSCHgCHzOCHgCHzOCHgCHgS CHzOCHzCHzSCHzOHzO CH CH OCHgCH SCHzCH OCHs A mixture of 2.3 g. (0.1mole) 'of sodium, 9.1 g. (0.05

mole) of 1,2-bis(2-mercaptoethoxy)ethane and 13.9 g. (0.1 mole) of methoxyethyl bromide in 100 ml. of ab- 1 solute ethanol was refluxed on a steam bath for 2% hours, after which the solvent was stripped off with a'water aspirator, and the residue was extracted with threeSO-ml. portions of hot ethyl acetate. The extracts were dried over anhydrous sodium sulfate, the so-lvent was removed and the residuefdistilled in vacuum to give the product boiling at 174 C./1 mm. 7

Analysis.-Calod. for C I-1 0 8 C, 48.3; 21.5. Found: C, 48.4; H, 8.7; S, 21.4.

Exam ple 5 .Prepamti0n of 3,6, 9,1 5 ,1 8,21 -l'z exam- 1 Z-thiotricosane CH CH OCH CH OCH CH OCH CH SCH 5.3 g. (0.05 mole) of sodium carbonate, 4.7 g. (0.05 mole) of ethane dithiol, and19.7 g. (0.1 mole) of ethoxycra ocracrnocH;cr-r,ocrr orr,'+zrranr A solution of 9 g. (0.0375 mole) of sodium sulfide nonahydrate in 25 ml. of Water, and 18.1 g. (0.075 mole) of ethoxyethoxyethoxyethyl bromide in 50 ml. of ethanol was refluxed with a water aspirator, t ill cloudiness appeared, after which the mixture was extractedwith ethyl acetate. Drying the extract over anhydrous sodium sulfate, followed by removal-of the ethyl acetate and distillation in vacuum gave a product boiling at 172 C./1 mm.

Analysis-eCalcd. for .C H O S: C, 54.3; H,'9.6; S, 9.0; mol. wt., 354. Found: C, 53.8; H, 9.7; S, 9.1; mol. wt., 33 6. i

Example 6 .-Preparation of 3,9,12,18-ttr0xa- 6,15-dithz'aeic0snne V N21 00: 2CH GHOCH2CH2Bt HSCHzCHrOCHsOHzOCHCI-IzSH CHsCHsOCHzCHaSCHzCHzO OHZCHQO CHzCHzSCHzCHzO CHzCHa Following the procedure of Example 1 above, using 5.3 g. (0.05 mole) of sodium carbonate, 9.1 g. (0.05 mole) of 1,2-bis(2-mercaptoethoxy)ethane, and 15.3 g. (0.1 mole) of ethoxyethyl bromide in 50 percent ethanol, 21 product was obtained which boiled atf172174 C./ 1 /2 mm.

Analysis-Calm. for C H O S2: C, 51.5; H, 9.2; S, 19.7; mol. wt. 326. Found: C, 51.0; H, ,9.0; S, 19.6; mol.

Example 7.Preparation 0f 3,9,l5-tri0xa6,12-dithiahep tadecane Example 8 5,1 8-tetroxa-9,12*dithiaeic0sane zonsontoonzonzoomon nr Hsomomsri OHsCHgOCHgCHzOCHQCHzSOHgCHgSCHzOHgOCH CHzOCHgCHg Following the procedure of Example, 1 above, using ethoxyethyl bromide in 50 percent ethanol, a product was obtained which boiled at 172173 C./2 /2 AnaZysis. -Calcd. for C H O S .C, 51.5; H, 9.2; S,

19.7. Found: C, 511; H, 8.9; S, 19.4. V

0 Example 9.Preparati0n 0f 1,17-dihydr0xy-3,9,15-tri0xa- 6,1Z-dithfaheptadecane-4,14-di0ne HSVCHZCHZOCHZCHZSITI 2BrCH COOCI-I CH' OH- HOCH 'CH OOCCH SCH CH OC H CH SCH;COOCH CH OH A mixture of 2.65 g- (0.025 mole) of sodium carbonate, 3.45 g. (0.025 mole) of bis mercaptoethyl ether, and 9.15

g. (0.05 mole) of hydroxyethyl bromoacetate in 50 ml. of 50 percent ethanol was refluxed on a steam bath overnight. Most of the ethanol was distilled off and the cloudy residual mixture was extracted with three 50-ml. portions of ethyl acetate. After drying the extracts over anhydrous sodium sulfate, removal of the ethyl acetate in vacuum at room temperature left the product as a light tan oil.

Analysis.-Calcd. for C H O S C, 42.1; H, 6.4; S, 18.7. Found: C, 41.4; H, 6.0; S, 18.9.

Example 10.Preparation of 1,23-dihydr0xy-3,6,12,1 8,-

21pent0xa-9,I5-dithiazric0sane-7,1 7 -di0ne HS CHzCHzO CHzCHzSH NagCOg 2BrCHgC O O CHgCHzO CHgCHzOH H0 CHzCHgO CHZCHZO O COH2SCH2CHZ O OHzCHaSCHgC O O CH CH O OHZCHBOH Following the procedure of Example 9, using 2.65 g. (0.025 mole) of sodium carbonate, 3.45 g. of his mercaptoethyl ether, and 11.35 g. (0.05 mole) of hydroxyethoxyethyl bromoacetate, the product was obtained as a syrupy oil.

Example 11.Preparati0n of 1,20-dihydr0xy-3,9,12,18- tetr0xa6,15-dithiaeic0sane-4,17-di0ne HSOHzCHgO CHzCHnO CHgCHzSH Na COa 2BrCHgGO O CH CHgOH HOGHaCHzO 0C CHzSCHzCHzO CH2 CHzO CHzCHzSOHzC O O CHzCHzOH Following the procedure of Example 9 above, using 15.6 g. (0.147 mole) of sodium carbonate, 26.75 g. (0.147 mole) of 1,2-bis(Z-mercaptoethoxy)ethane, and 55 g. (0.3 mole) of hydroxyethyl bromoacetate, the prodnot was obtained as a syrupy oil.

Analysis.Calcd. for C14H2608S2: C, H, S, 16.7; mol. wt., 386. Found: C, 42.8; H, 6.9; S, 16.8; mol. wt., 397.

Example J2.-7,10-dioxa-4,.I3-dithiahexadecane-2,15-dicarboxamiae; reaction of methacrylamide and bis(2-mercapt0ethoxy ethane CH 2CHz=JJCONH2 HSCH2CH2O CHZCHZOCHZCHZSH CH CH Seventeen grams of methacrylamide (0.2 mole), 18.2 g. of bis(2-mercaptoethoxy)ethane (0.1 mole), and 16 drops of benzyl trimethylammonium hydroxide solution were dissolved in 250 ml. of ethanol. After 11 hours of refluxing, the solvent was evaporated and the solid remaining was recrystallized from ethyl acetate. Fourteen grams of material melting at 71-74 C. were obtained.

Analysis.Calcd. for C H N S O C, 47.8; H, 7.8; S, 18.2; N, 7.9. Found: C, 47.2; H, 8.0; S, 17.4; N, 7.5.

Example 13.Preparation.= of 2,5,11,14,20,23-hex0xa- 8,17-dithiatetrac0sane-6,19-di0ne HSOHQCHZO CHzCHgO CHfiCHZSH O ZCHaOCHgCHzO f CHgBr 0 01130 CHzCHgO g CHZSCHQCHZO CH 0 CH O OHzCHzSCHz O CHzOHgO CH Following the procedure of Example 12, using 6.2 g. (0.05 mole) of sodium carbonate monohydrate, 9.1 g. (0.05 mole) of 1,2-bis(Z-mercaptoethoxy)ethane, and

Example 14.Preparati0n 0 f 2,5 ,1 I ,1 7,2 O-pentoxa- 8,14-dithiaheneicosane6,16-di0ne H CH CHgCHzO lCHzSCHgCHzOCHzCHgSCHzC 0 CHQOHZO CH3 A mixture of 5.3 g. (0.05 mole) of sodium carbonate, 6.9 g. (0.05 mole) of his mercaptoethyl ether, and 19.7 g. (0.1 mole) of methoxyethyl bromoacetate in ml. of 50 percent ethanol was refluxed on a steam bath for 6 hours, after which most of the ethanol was distilled off. Upon cooling, a heavy oil separated, which was drawn off. The aqueous residue was extracted with three portions of ethyl acetate'totaling 200 ml., and the combined oil and extracts were dried over anhydrous sodium sulfate. Removal of the solvent, followed by distillation in vacuum gave the product boiling at 207-210 C. at 2 mm.

Analysis.Calcd. for C H O S C, 45.4; H, 7.0; S, 17.3. Found: C, 45.5; H, 7.0; S, 18.5.

The novel sensitizers of our invention have properties quite different from the sulfur compounds disclosed in Schwan and Dann US. application Serial No. 137,041, filed September 11, 1961, in that they do not have strong fogging tendencies as do the componds of the Schwan and Dann application. Moreover, the sensitizers of the present invention have properties quite different from the corresponding compounds containing only oxygen atoms in the positions occupied by sulfur in the present compounds. The oxygen compounds have little or no sensitizing action.

The invention has been described in detail with particu lar reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

What we claim as our invention and desire secured by Letters Patent of the United States of America is:

1. A compound of the formula:

llii O wherein R represents a member selected from the class consisting of hydroxyl, alkoxyl containing from 1 to 4 carbon atoms and carbamyl radicals, R represents a member selected from the class consisting of hydrogen and methyl, each of X and X is a different divalent radical selected from the class consisting of oxygen and sulfur atoms, In is an integer of from 0 to 1 and n is an integer of from 0 to 2.

2. The compound represented by the following formula:

HOCH CH OOCCH SCH CH OCH CH SCH COOCH CH OH 3. The compound represented by the following formula:

HOCH CH OCH CH OOCCH SCH CH OCH CH SCH COOCH CH OCH CH OH 4. The compound :epresante'd by the following for References Cited by the Examiner: mula: r V UNITED STATES PATENTS V HOCHZCHZOOCCH2SCH2CH2OCH2 7 2,603,616 7/52 Newton 260-481XR CH20CH2CH2SCH2C00CH2CH20H 5 2,679,526, *5/54 De'Groote 260-4181 5. The compound represanted by the following for- 2,900,368 8/ 59 Stilmal' mula: 2,962,524 11/60 Hostettler et a1. 260481 0 v FOREIGN PATENTS OHQOGHQCHflOC/HISCHZOHQOOHZCHEOCHfiSCHfl OCHZCHiOCHS 54 454 5 Great Britain 6. The compound represmted by the following for- 10 Q mula: LORRAINE A. WEINBERGER, Primary Examiner.

0 LEON ZITVER, Examinen,

I II 011 0 CH CH O l] GHZSCHzCH OCHgOHgSOHgC O CHZCHEO CH 

1. A COMPOUND OF THE FORMULA: 